Insurgents have launched a rocket attack on the main coalition military base in Afghanistan's Helmand Province.

The heavily fortified Camp Bastion, which accommodates up to 4,000 UK, American, Danish and Estonian troops, was targeted at about 6.30pm local time as darkness fell on Wednesday.

A Ministry of Defence spokesman said: "We can confirm that a rocket attack against Camp Bastion took place on February 27, 2013. No significant damage or casualties have been reported as a result of this incident."

Multiple explosions could be heard minutes after the IDF (indirect fire) alarm sounded inside the sprawling desert base. Forty minutes later the all-clear was announced and troops were directed to search their immediate area for unexploded ordnance and casualties.

This latest attack comes as UK forces Helmand prepare to hand over to the next deploying brigade in what is known as the RIP (relief in place). Last September two US Marines were killed and six Harrier jets destroyed after militants breached the perimeter fence and attacked through the airfield on Camp Bastion.

The Taliban said Prince Harry who was in theatre as an Apache helicopter pilot at the time, was the intended target but Nato officials said the young royal was never in any danger. Insurgents claimed the attack which resulted in a four-hour fire-fight that has become known as the 'Battle of Bastion' was in response to an amateur US-made film mocking Islam.

Last March US Defence Secretary Leon Panetta also escaped injury after an attempted suicide bomb attack as his plane touched down at Camp Bastion. A locally employed civilian worker stole a vehicle and tried to drive towards the runway while setting himself alight.

In 2007 a suicide bomber detonated a device at the perimeter gate but the vast blast walls prevented any injuries to service personnel.

Camp Bastion, an isolated 37km by 67km base is in the middle of Helmand's inhospitable desert. Its location was specifically selected so that coalition forces could see for miles from all angles. It is also protected from the air.

When it was built in 2006 it was completely remote. However, more recently compounds have sprung up in the unoccupied land surrounding the base which have been exploited by the Taliban elements.